There was also a post on one of the Sun blogs with a little bit of history of OpenStep for Solaris, which is on the Archive too, at https://web.archive.org/web/20060215231443/http://blogs.sun.com/roller/page/richb?entry=openstep_history
Some of the archived comments talk about the Lighthouse apps...
For a long time I thought that the Lighthouse Office Suite would be unobtainium forever, but it seems someone uploaded them to nextcomputers.org in 2016, and I missed it? (www.nextcomputers.org/NeXTfiles/Software/NEXTSTEP/Apps/Lighthouse_Design/)
Not sure if any of those run on non-m68k hardware though (the FrameMaker in that directory seems to be NeXT/Intel/HPPA according to the package name - not quad-fat for OPENSTEP/Sparc).